Abstract：
Acid-sensing ion channels (ASICs) are trimeric proton-gated cation channels that play a role in neurotransmission and pain sensation. The snake venom-derived peptides, mambalgins, exhibit potent analgesic effects in rodents by inhibiting central ASIC1a and peripheral ASIC1b. Despite their distinct species- and subtype-dependent pharmacology, previous structure-function studies have focussed on the mambalgin interaction with ASIC1a. Currently, the specific channel residues responsible for this pharmacological profile, and the mambalgin pharmacophore at ASIC1b remain unknown. Here we identify non-conserved residues at the ASIC1 subunit interface that drive differences in the mambalgin pharmacology from rat ASIC1a to ASIC1b, some of which likely do not make peptide binding interactions. Additionally, an amino acid variation below the core binding site explains potency differences between rat and human ASIC1. Two regions within the palm domain, which contribute to subtype-dependent effects for mambalgins, play key roles in ASIC gating, consistent with subtype-specific differences in the peptides mechanism. Lastly, there is a shared primary mambalgin pharmacophore for ASIC1a and ASIC1b activity, with certain peripheral peptide residues showing variant-specific significance for potency. Through our broad mutagenesis studies across various species and subtype variants, we gain a more comprehensive understanding of the pharmacophore and the intricate molecular interactions that underlie ligand specificity. These insights pave the way for the development of more potent and targeted peptide analogues required to advance our understating of human ASIC1 function and its role in disease.
摘要：
酸感应离子通道（ASIC）是三聚体质子门控阳离子通道，在神经传递和痛觉中起作用。蛇毒衍生的肽，mambalgins,通过抑制中枢ASIC1a和外周ASIC1b在啮齿动物中表现出有效的镇痛作用。尽管它们不同的物种和亚型依赖性药理学，以往的结构-功能研究主要集中在mambalgin与ASIC1a的相互作用上.目前,负责这种药理作用的特定通道残基，ASIC1b的mambalgin药效团仍然未知。在这里，我们确定了ASIC1亚基界面上的非保守残基，这些残基驱动mambalgin药理学从大鼠ASIC1a到ASIC1b的差异，其中一些可能不会产生肽结合相互作用。此外,核心结合位点下方的氨基酸变异解释了大鼠和人ASIC1之间的效力差异.手掌域内的两个区域，这有助于mambalgins的亚型依赖效应，在ASIC门控中起关键作用，与肽机制中的亚型特异性差异一致。最后,ASIC1a和ASIC1b活性有一个共享的主要mambalgin药效团，某些外周肽残基对效力显示出变体特异性意义。通过我们对不同物种和亚型变体的广泛诱变研究，我们获得了一个更全面的了解药效团和复杂的分子相互作用的基础上，配体的特异性。这些见解为开发更有效和靶向的肽类似物铺平了道路，这些肽类似物需要提高我们对人类ASIC1功能及其在疾病中的作用的低估。
